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基于线路电压降的双回线解列运行判据
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作者 索南加乐 罗云照 +1 位作者 吴亚萍 祖拉提 《西安交通大学学报》 EI CAS CSCD 北大核心 2003年第2期119-122,共4页
通过对双回线非全相运行时同名相差电流的分析,提出了一种利用同名相电压降判别双回线解列运行的新方法.该方法考虑了零序电流和两回线长度不相等因素,能有效判别双回线非全相解列运行状态.仿真结果表明,该方法在双回线各种非全相并列... 通过对双回线非全相运行时同名相差电流的分析,提出了一种利用同名相电压降判别双回线解列运行的新方法.该方法考虑了零序电流和两回线长度不相等因素,能有效判别双回线非全相解列运行状态.仿真结果表明,该方法在双回线各种非全相并列运行状态下,修正后的差电流明显小于修正后的和电流,在各种解列运行状态下修正后的差电流大于修正后的和电流,不会发生误判. 展开更多
关键词 电压降 回线解列运行 电力系统 继电保护 差动保护 零序电流 回线长度
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瞬变电磁法在地下洞体探测中的应用研究 被引量:1
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作者 祝卫东 张瑛颖 《建筑技术开发》 2008年第11期30-32,40,共4页
地下洞体探测是地质勘探中的一个重要课题。分析了利用瞬变电磁法探测地下洞体的若干成功案例,对不同地质环境、不同特征地下洞体的瞬变电磁探测方法应用进行了试验研究,充分认识了地下洞体的异常体形态特征,熟悉掌握了应用瞬变电磁法... 地下洞体探测是地质勘探中的一个重要课题。分析了利用瞬变电磁法探测地下洞体的若干成功案例,对不同地质环境、不同特征地下洞体的瞬变电磁探测方法应用进行了试验研究,充分认识了地下洞体的异常体形态特征,熟悉掌握了应用瞬变电磁法的技术要点。同时结合实际工程项目进行了有效验证,积累了较好的经验,为今后的地质找矿或地质灾害勘查提供了技术储备。 展开更多
关键词 瞬变电磁法 地下洞体 回线长度 低阻覆盖厚度 勘探深度
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Vegetation Growth Monitoring Under Coal Exploitation Stress by Remote Sensing in the Bulianta Coal Mining Area 被引量:4
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作者 LU Xia HU Zhen-qi LIU Wei-jie HUANG Xiao-yan 《Journal of China University of Mining and Technology》 EI 2007年第4期479-483,共5页
Coal exploitation inevitably damages the natural ecological environment through large scale underground exploitation which exhausts the surrounding areas and is the cause of surface subsidence and cracks. These types ... Coal exploitation inevitably damages the natural ecological environment through large scale underground exploitation which exhausts the surrounding areas and is the cause of surface subsidence and cracks. These types of damage seriously lower the underground water table. Deterioration of the environment has certainly an impact on and limits growth of vegetation,which is a very important indicator of a healthy ecological system. Dynamically monitoring vegetation growth under coal exploitation stress by remote sensing technology provides advantages such as large scale coverage,high accuracy and abundant information. A scatter plot was built by a TM (Thematic Mapper) infrared and red bands. A detailed analysis of the distributional characteristics of vegetation pixels has been carried out. Results show that vegetation pixels are affected by soil background pixels,while the distribution of soil pixels presents a linear pattern. Soil line equations were obtained mainly by linear regression. A new band,reflecting vegetation growth,has been obtained based on the elimination of the soil background. A grading of vegetation images was extracted by means of a density slice method. Our analysis indicates that before the exploitation of the Bulianta coal mining area,vegetation growth had gradually reduced; especially intermediate growth vegetation had been transformed into low vegetation. It may have been caused by the deterioration of the brittle environment in the western part of the mining area. All the same,after the start of coal production,vegetation growth has gradually improved,probably due to large scale aerial seeding. Remote sensing interpretation results proved to be consistent with the actual situation on the ground. From our research results we can not conclude that coal exploitation stress has no impact on the growth of vegetation. More de-tailed research on vegetation growth needs to be analyzed. 展开更多
关键词 coal exploitation linear regression density slice vegetation growth
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